Cyclobutrifluram (TYMIRIUM® technology): Low risks of a soil applied nematicide and fungicide to non-target soil invertebrates and bees

Abstract

Cyclobutrifluram (TYMIRIUM® technology) is a seed- and soil-applied nematicide and fungicide which protects the plant root mass. Cyclobutrifluram acts by inhibiting mitochondrial complex II electron transport and succinate dehydrogenase inhibition (SDHI). Concerns over the potential adverse effects on non-target species were addressed by assessing whether recommended field application rates of cyclobutrifluram would result in adverse impacts on soil invertebrates or honeybees. Studies conducted under laboratory conditions with the active ingredient and two formulations provided No Observed Effect Concentrations for earthworm (Eisenia andreii )reproduction of 71-171 mg a.i./kg dry soil with no effects on soil mite (Hypoaspis aculifier) reproduction. There were no effects on honeybee (Apis mellifera) adults or larvae following chronic exposure to doses up to 400 and 160 mg/kg diet respectively. Using Brazil as a target market (soybean seed treatment and in-furrow application in fruiting vegetables), our laboratory studies indicate that the risk to two species of soil invertebrates and honeybees of the use of cyclobutrifluram either in-furrow or as a seed treatment was orders of magnitude below any levels of concern.